Auditory bulla

“ Of those persons to whom music is but a confused mass of sounds, we may remark that almost all sing false. We are forced to think that they have the auditory apparatus so made, as to receive but brief and short undulation, or that the two ears not being on the same diapason, the difference in length and sensibility of these constituent parts, causes them to transmit to the brain only an obscure and undetermined sensation, like two instruments played in neither the same key nor the same measure, and which can produce no continuous melody. ”

“ Such obstructions may exist in the middle-ear [p. 837] cavity, as thickening of the soft tissues of the middle ear, exudations and adhesions, as found in chronic catarrh, or in the external canal, as impacted cerumen, a swollen canal, etc. The effect of such obstruction would be to interrupt the normal sound-vibrations and cause them to be reflected back again to impress for a second time the auditory nerve-elements, causing an abnormal and therefore recognized condition. This is the most frequent variety of tinnitus, and for the reason that it is produced by the more ordinary ear diseases. ”

“ Again, the perforation of the drum, especially when it follows a catarrh, may cause a definite auditory illusion with regard to the sound of voices, or the illusion may be effected by the irritation of the skin in the ear passage, or{446} by anemia, or by a strong carotid pulse and a distention of the bloodvessels, as happens in alcoholism. Many people become abnormally sensitive to sound at the beginning of fevers. Women at the time of their climacterium hear all kinds of voices. Inasmuch as this soon stops, the abnormality and incorrectness of their audition is hard to establish. ”

“ As the hind foot elongates the index will increase; elongation of the hind foot is interpreted as a specialization.
The Cranial index (breadth across bullae/length of the skull × 100) reflects the degree of development of the tympanic or mastoid region, or both, and is thought to be an adaptation for more acute hearing and possibly for more delicate balance. Inflation of the tympanic bullae is thought to be a specialization. As the auditory bullae become more inflated, the index increases toward 100. ”

“ One source of danger to the hearing consists in lowering the temperature of the ear, especially by the introduction of cold water into the auditory canal. Every one is familiar with the unpleasant sensation of distension and the confusion of sounds which accompany the filling of the ear with water when bathing: the weight of the {225}water within it really distends the membrane, and the cold chills the adjacent sensitive parts. It is not surprising, therefore, that the frequent introduction of cold water and its continued presence in the ear enfeeble the sense of hearing. ”

“ Bartholinus, Lycosthenes, Pare, Schenck, and Oberteuffer have remarked on deficient external ears. Guys, the celebrated Marseilles litterateur of the eighteenth century, was born with only one ear. Chantreuil mentions obliteration of the external auditory canal in the new-born. Bannofont reports a case of congenital imperforation of the left auditory canal existing near the tympanic membrane with total deafness in that ear. Lloyd described a fetus showing absence of the external auditory meatus on both sides. ”

“ If a person on blowing the nose violently, feel a swelling in the ear, from the membrane of the tympanum being forced outwards, the tube is open; and though the tube be closed, if the beating of a watch placed between the teeth, or pressed against the side of the head, cannot be heard, the operation cannot relieve, as the sensibility of the auditory nerve must have been destroyed. In a closed Eustachian tube, there is no noise in the head, like that accompanying nervous deafness. ”

“ The form of passive motion which acts most naturally here is that of sound. This form of passive motion, augmented as it is by means of the ear-trnmpet, acting frequently and systematically upon the ear, prevents further anchylosis, and the fatty degeneration of the auditory nerve that comes from desuetude. This, of course, tends to a permanent improvement of the hearing, and in some cases patients come to hear without the trumpet.
Preparations for the New York meeting of the American Association, to begin August 10th, are being carried vigorously forward. ”

“ It is a very common ear disorder. The opening into the ear is about an inch long, or a little more, and is separated from that part of the ear within, which is known as the middle ear, by the eardrum membrane. The drum membrane is a thin, skinlike membrane stretched tightly across the bottom of the external opening in the ear or auditory canal, and shuts it off completely from the middle ear within, and in this way protects the middle ear from the entrance of germs, dust, and water, but only secondarily aids hearing. ”

“ In all the Amphibia, Sauropsida and Mammalia, except the Urodela and a few Anura and Reptilia, the first visceral or hyomandibular cleft enters into intimate relations with the organs of hearing, and from it and the adjoining parts are formed the tympanic cavity, the Eustachian tube, the tympanic membrane and the meatus auditorius externus. The tympanic membrane serves to receive from the air the sound vibrations, which are communicated to fluids contained in the true auditory labyrinth by one ossicle or by a chain of auditory ossicles. ”

“ Disease of the ear may obviously act in the same way, but, even apart from actual disease, various nervous disturbances favour the production of auditory hallucinations during sleep, and, in marked cases, even awake.
We may dream of listening to music in the absence of all external sounds having any musical character. In such cases, no doubt, the actual conditions [78] within the auditory mechanism are suggesting music to the brain, but the resulting music seems usually to be less definite, less rememberable, than when it forms around the nucleus of an external series of sounds. ”

“ Probably all the laity, so to speak, when first they realize that their hearing is diminished, believe that the wax has accumulated and has blocked the auditory canal. The sensation to them is certainly one of obstruction, and they seem justified in picking at the canal of the ear in attempting to remove the obstructing substance. ”

“ In all cases of congenital deafness it will be found that there exists some disorganization of the organ of hearing itself, some obstruc tion in the internal ear or compression of the auditory nerve, whereby the vibrations of the ear are prevented from pro ducing the required effect upon the internal parts of the ear, or from being communicated to the brain. ”

“ We all have our limits, and that limit may be quickly found by these whistles in every case. The facility of hearing shrill sounds depends in some degree on the position of the whistle, for it is highest when it is held exactly opposite the opening of the ear. Any roughness of the lining of the auditory canal appears to have a marked effect in checking the transmission of rapid vibrations when they strike the ear obliquely. ”

“ It may be cured, particularly at its commencement, by the application of such stimulants as are capable of exciting a discharge from the ceruminous glands; for which purpose thev should be introduced into the meatus auditorius.
In some cases of this kind, where the auditory nerve has been in some degree torpid, or rather perhaps where there has been a kind of paralysis, or want of action, in the muscles which brace the membrane of the tympanum, and keep the chain of bones in their proper state; a person has not been able to hear, except during a considerable noise. ”

“ Research has shown us that hearing loss can sometimes be alleviated, corrected, or best of all, prevented. Scientific investigators supported by the Federal government's National Institute of Neurological and Communicative Disorders and Stroke and by professional societies and voluntary health organizations are learning more about how the auditory system works, and what can go wrong and why. Innovative programs in research, education, and prevention have long been conducted and supported by many voluntary agencies working on behalf of the hearing impaired. ”

“ And though, in the case of hearing, we cannot so clearly trace the connexion of cause and effect, yet as we see that the auditory apparatus is one fitted to intensify those vibrations constituting sound, and to convey them to a receptacle containing liquid in which nerves are immersed, it can scarcely be doubted that the sensation of sound proximately results from molecular re-arrangements caused in these nerves by the vibrations of the liquid: knowing, as we do, that the re-arrangement of molecules is in all cases aided by agitation. ”

“ Bezold has examined a large number of human ears of different ages and indicates that after the fiftieth year there is not only a successive decrease in the number of the approximately normal-hearing, but there is a successively growing increase in the degree of auditory limitation which the ear experiences with increasing age. ”

“ If this process is going on in the same medium (the air) in which our ear is situated, the membrane will at every condensation be forced toward the hollow of the drum, and at every rarefaction will move itself in the opposite direction.
These vibrations necessitate a similar motion of the auditory ossicles, and thereby a transference to the auditory nerves is effected.
The greater the condensation of a sound-conducting medium at any given moment, the greater also will be the amplitude of vibration of the membrane and of the auditory ossicles and of their action ”

“ Patients suffering from chronic cerebral anæmia are afflicted with morbid irritability of the optic and auditory nerves. Loud sounds and bright lights are very annoying to them. Roaring, buzzing, and beating sounds in the ear are common, and scintillations, muscæ volitantes, and temporary darkening of the visual field—particularly noticed when the head is suddenly raised—are complained of in all cases. It is often found that the tinnitus disappears and the hearing power improves on assuming the horizontal position. ”

“ Cold water should not be allowed to enter the auditory canal. If the wax accumulate, never remove it with a hard instrument, lest the delicate membrane be injured, but with a little warm water, after which turn the head to let the water run out, and wipe the ear dry. The hair around the ears should never be left wet, as it may chill this sensitive organ. If an insect get in the external ear, pour in a little oil to kill it, and then remove with tepid water. The object of the Eustachian tube is to admit air into the ear, and thus equalize the pressure on the membrane. ”

“ It is believed that each is sensitive to a particular vibration rate and that each is also attached to a nerve fiber. The sound waves of the air transmitted by the tympanum, the ear bones and the liquid of the internal ear start sympathetic vibrations in the strings of the cochlea which affect the auditory nerve and we hear. The highest tones perceptible by the human ear are produced by from 24,000 to 40,000 vibrations per second. The average person cannot hear sounds produced by more than about 28,000 vibrations. ”

“ The external ear consists of an expanded portion known as the pinna or auricle, and of a passage, the auditory canal or meatus, leading inwards from it. The surface of the auricle is convoluted to collect and transmit the vibrations of air by which sound is produced the auditory canal conducts these vibrations to the tympanic membrane. Many animals move the auricle in the direction of the sound. Thus the horse pricks up its ears when it hears a noise, the better to judge of the direction of sounds. ”

“ If the stricture or point of occlusion of the auditory canal is limited and composed of membranous and fibrous tissues, a good result can be usually obtained, and there is no reason why complete recovery of hearing should not take place if the labyrinth and tympanic cavity are normal. ”

“ The observation just recorded appears to lead to the following conclusions with reference to the development of the auditory nerve. A single rudiment arises from the brain for the auditory and seventh nerves. This rudiment subsequently [Pg 422] becomes split into two parts, an anterior to form the seventh nerve, and a posterior to form the auditory nerve. The ganglionic part of the auditory nerve is derived from the primitive outgrowths from the brain, and not from the auditory involution. ”

“ This end-organ in the cochlea may be compared very fitly to the telephone which receives the message, and that portion of the brain where the auditory tract ends, to the telephone at the distant end of the path, the listener there representing consciousness. The auditory path within the brain is long and complicated, there being, in fact, many way-stations through which the message passes before it reaches the final one. ”

“ A distinction is generally made in physics between sound and noise. Noise affects our tympanic membrane as an irregular succession of shocks and we are conscious of a jarring of the auditory apparatus; whereas a musical sound is smooth and pleasant because the tympanic membrane is thrown into successive periodic vibrations to which the auditory receptor (sense organ of hearing) has been attuned. To produce musical sounds, a body must vibrate with the regularity of a pendulum, but it must be capable of imparting sharper or quicker shocks to the air than the pendulum. ”